Have any of you tried revving your p650 with the airfilter off while looking into the air intake?? After oil leaked into the air box, I cleaned it out and did just this. Is it normal for flames to erupt from the carbs? One cylinder or the other will backfire and shoot flames. It only has 13 hours on it. ANY ideas, input or comments??

Thanks!

 

Most machines do this a little when the engine is cold and it is cold outside. I call it coughing, some call it sneezing. It is due to lean. When the engine warms up it should not do this at all, or bad things could happen.

Electronic FI autos don't do this at all because they richen the mixture up properly when cold. Some well adjusted choked carburetors pretty much prevent this.

These overly simple motorcycle carbs with a flimsy enrichment circuit sometimes do this a lot. My brother's 400 almost never does it, but it runs so rich that it bogs a bit on a hot day.

Lean misfires can sometimes burn really really slow, that is why there is still a flame left in the cylinder after the exhaust stroke and it ignites the air in the intake pipe. No biggy.

 

Howdy,
I think he means that it backfires when the filter is out of the air box. Mine will do that also. It is lean from removing the filter and lid of the box. Mine does that also. Have a goodun!!!

 

Yeah, I know. Many quads do that even with the filter installed. Mine does.

I think I need to set my needles one notch richer, since it seems to be a little leaner after my muffler mod.

 

Thank you Master Nyroc and Ross 650. Skipping all the technical jargon, I assumed that it was normal, but wanted to be sure. Thanks for your help! Nyroc, your website is very informational and very well done. Thanks for sharing.

This is off topic, but I have another question. If I were to order an HMF pipe for it, am I correct in thinking that it would improve the power throughout the entire powerband even without any further mods? At this point, my machine is completely stock and has already outran the twin to MIke Penland's 650 in a quarter mile drag. After experiencing that, it is hard to believe that I can get a benefit from mods.

 

Are you saying that your stock 650 outran a PBR modified 650 or one that looks like a PBR quad? Last time I talked to Mike he told me that with a few of his upgrade parts people were getting 74 mph out of their machines. Also Mike doesn't even run a clutch kit in his bike, he removes stuff to cut the weight and increase acceleration, Kilby is the one who has the performance machine.

 

It could just be that it looks like it? This thing has a ton of mods, though. I saw that they are calling it a twin here: website

(last post of that forum)

Like I said, it was just a quarter mile drag, we ran them about six times. Not to say mine would do as well in a race, I don't know yet, but will find out Sunday. And the guy talking in that link is not the one that was riding when we raced them.

 

It sounds like they're saying it is a copy of Mike's bike. If so it should haul ***** in acceleration as about 75 lbs has been shaved from that machine. I'm truly unfamiliar with the "twin" they are talking about though. May be some of our more knowledgeable members will have more insight. It is possible that you can just plain ride better and have a strong machine too.

 

Weight would have been a factor. The riders on the other two 650's were probably at least 50 pounds more than me.